By combining brute force and gentle understanding cops can get the criminal to confess to his crime. The problem is, that might not actually work

It’s a classic scene, found in nearly every television show and movie about crime and cops. There’s a good cop and a bad cop, and by combining brute force and gentle understanding, they get the criminal to confess to his crime. The problem is, this strategy might not actually work.

New research from the University of Portsmouth recently reenacted a good cop, bad cop scenario with research subjects. Students were assigned groups—they would either be telling the truth about a job they really had, or assigned a fictional job that they were going to lie about. With three days to prepare, the students were then asked detailed questions about their job. For both groups, the person asking the questions was neutral. It was the person taking notes who varied. Sometimes they were the good cop, nodding and smiling as the person spoke. In other cases they were bad, frowning and shaking their head during the note taking.

Here’s the headline result – the truth-telling participants gave more detailed answers than the liars, but only when the second interviewer provided a supportive presence. This runs entirely counter to the aggressive questioning styles so often portrayed in fiction. By creating a reassuring atmosphere, the second interviewer encouraged the honest interviewees to open up more, which made the the lack of detail given by liars stand out.

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About Rose Eveleth

Rose Eveleth is a writer for Smart News and a producer/designer/ science writer/ animator based in Brooklyn. Her work has appeared in the New York Times, Scientific American, Story Collider, TED-Ed and OnEarth.